1. I find myself constantly looking at the sky when some dramatic clouds fly over it: http://www.flickr.com/photos/38912116@N00/373754256/. You also get nice sun rays through the holes in the clouds sculpting the landscape and giving it a dramatic posture.
2. The sun standing low over the horizon also increases the 3D-effect of landscapes and also gives incredible colors that change fast
Add (1) and (2) and you can almost sit still and have a complete photo session just watching the clouds fly by and the sun change the color.
3. Another favorite is shooting at beaches where the sky is reflected in the wet sands. Plus the structures in the sand...
Look here for an example: http://www.flickr.com/photos/38912116@N00/373750314/ of what I mean (location: Bergen aan Zee, The Netherlands)

Hope to find some dramatic clouds and light @ New Zealand...

B.t.w.: Are there any limits, if you shoot a landscape with the sun shining into your lens? Burning a hole in your sensor ?

That's just as it came out of my Sony P200 set to automatic (it applied f/5,6 and 1/400 sec) with D-Lighting set to 1 (out of 100) afterwards in CaptureNX - which made the blacks a little deeper.
No filters, no other trick. It's just that special combination of sun and clouds that I so love...

hi tombomba2,
Yes, i know exactly what you mean. I also look for interesting cloud formations which can be very dramatic and add so much to a landscape scene. i'm also trying to improve on capturing rays breaking through clouds:

I took this shot this weekend of the 2010 Fifa World cup Stadium being built in Cape Town (I only wish they would hurry up a bit!)